Studies in our laboratories have indicated that Resonance Raman (RR) spectroscopy of chromophores bound to biomacromolecules is useful for determination of binding interactions. Using this technique we have determined the ionization state, conformation, metal-ligand interaction and other structural details of the chromophore boundto a biomacromolecule. Preliminary data indicate that flawins and flavoproteins give RR spectra at concentrations of approximately or equal to 1 x 10 to the minus 4th power M; we propose to study the RR spectra of several flavin systems and flavoproteins. Specifically, we propose studies on charge transfer complexes of D-amino acid oxidase and on semiquinones formed from glucose oxidase. These species have intense visible absorption at argon-ion laser emission frequencies and would be expected to give RR spectra by excitation at these frequencies. We also propose improvements in our instrumentation which should enable us to obtain spectra at lower concentrations by increasing signal-to-noise and decreasing fluorescence background. Among these improvements is a high powered krypton laser with emission in the 350 nm region. We propose experiments using 350nm excitation, designed to determine the conformaion of reduced flavin in flavodoxin and lactate oxidase. Finally, we propose experiments designed to determine whether RR spectroscopy is useful for establishing the position of substitution in isoalloxazines. These studies will be carried out in lactate oxidase, D-amino acid oxidase, and bacterial luciferase. Having studied the RR spectra of flavins, we propose to study substrate, product and intermediate complexes of general" fatty acyl CoA dehydrogenase. This enzyme is important because of its relationship to the control of fatty acid metabolism and to diseases such as artereoschlerosis and diabetes associated with altered fatty acid metabolism.